--- /dev/null
+<?php
+
+namespace Drupal\Tests\system\Functional\Module;
+
+/**
+ * Attempt disabling of required modules.
+ *
+ * @group Module
+ */
+class RequiredTest extends ModuleTestBase {
+ /**
+ * Assert that core required modules cannot be disabled.
+ */
+ public function testDisableRequired() {
+ $module_info = system_get_info('module');
+ $this->drupalGet('admin/modules');
+ foreach ($module_info as $module => $info) {
+ // Check to make sure the checkbox for each required module is disabled
+ // and checked (or absent from the page if the module is also hidden).
+ if (!empty($info['required'])) {
+ $field_name = 'modules[' . $module . '][enable]';
+ if (empty($info['hidden'])) {
+ $this->assertFieldByXPath("//input[@name='$field_name' and @disabled='disabled' and @checked='checked']", '', format_string('Field @name was disabled and checked.', ['@name' => $field_name]));
+ }
+ else {
+ $this->assertNoFieldByName($field_name);
+ }
+ }
+ }
+ }
+
+}